ABSTRACT
Nowadays, industrial and agricultural wastes based on alkali-activated binders have been introduced as environmentally friendly materials with high durability performance. We evaluated the performance of alkali-activated mortars (AAMs) incorporated with ceramic powder (WCP), ground blast furnace slag (GBFS), and fly ash (FA) as surface repair materials useful in the construction sector. Various levels of GBFS and FA replacing WCP were blended and activated via low concentration of the alkaline activator solution. The fresh and hardened state properties of these AAMs including the flow and setting time; compressive, flexural, and tensile strengths; abrasion resistance; bond strength; and compatibility with the base concrete substrate (NC) tests were performed. The microstructures and related characteristics of such mortars were also examined. The bond strength and other mechanical properties of the WCP-based AAMs were enhanced when FA was replaced by GBFS in the presence of low alkaline solution contents. The early bond strength after 24 hours increased from 1.8 MPa to 2.4 MPa when the GBFS level was raised from 30 to 70%, respectively. This increase in the AAM bond strength and improvement in the compressive strength as well as microstructure were ascribed to the formation of more calcium (aluminium) silicate hydrate (C-(A)-S-H) due to the increase in the calcium content. The obtained excellent abrasion–erosion resistance, freeze–thaw cycling resistance, and high compatibility with the concrete substrate confirmed the effectiveness of the proposed AAMs as high performance repair material effective for damaged concrete surfaces.
